The baseline intracluster entropy profile from gravitational structure formation

Voit, G. Mark; Kay, Scott T.; Bryan, Greg L.

doi:10.1111/j.1365-2966.2005.09621.x

Cited by 309 publications

(519 citation statements)

References 42 publications

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“…Once again, the data are compared with the results of the spectroscopic X-ray analysis, which highlights the much broader radial range accessible by the joint X-ray/SZ technique. The observed entropy profiles are compared with the prediction of numerical simulations using gravitational collapse only (Voit et al 2005).…”

Section: Joint X-ray/sz Analysismentioning

confidence: 99%

“…The thermodynamical properties of the gas retain information on the processes leading to the thermalization of the gas in the cluster's potential well, which is encoded in the gas entropy K = kT n −2/3 e . Gravitational collapse models predict that the entropy of stratified cluster atmospheres increases steadily with radius, following a power law with index ∼ 1.1 (Borgani et al 2005;Sembolini et al 2016;Voit et al 2005). However, nongravitational processes induce an additional injection of entropy and can therefore be traced through the departures from the theoretical predictions (Chaudhuri et al 2012).…”

Section: Introductionmentioning

confidence: 99%

“…The black line shows the expectation from purely gravitational collapse (Eq. (5), Voit et al 2005). The dashed and dashed-dotted vertical lines represent R 500 and R 200 , respectively.…”

Section: Joint X-ray/sz Analysismentioning

confidence: 99%

“…The red points show the spectroscopic X-ray measurements. The black curve represents the expectation of pure gravitational collapse (Voit et al 2005). …”

Section: Hydrostatic Massmentioning

confidence: 99%

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The XMM cluster outskirts project (X‐COP)

et al. 2017

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Galaxy clusters are thought to grow hierarchically through the continuous merging and accretion of smaller structures across cosmic time. In the Local Universe, these phenomena are still active in the outer regions of massive clusters (R > R500), where the matter distribution is expected to become clumpy and asymmetric because of the presence of accreting structures. We present the XMM-Newton Cluster Outskirts Project (X-COP), which targets the outer regions of a sample of 13 massive clusters (M500 > 3 × 10 14 M ) in the redshift range 0.04-0.1 at uniform depth. The sample was selected based on the signal-to-noise ratio in the Planck Sunyaev-Zeldovich (SZ) survey with the aim of combining high-quality X-ray and SZ constraints throughout the entire cluster volume. Our observing strategy allows us to reach a sensitivity of 3 × 10 −16 ergs cm −2 s −1 arcmin −2 in the [0.5-2.0] keV range thanks to a good control of systematic uncertainties. The combination of depth and field of view achieved in X-COP will allow us to pursue the following main goals: i) measure the distribution of entropy and thermal energy to an unprecedented level of precision; ii) assess the presence of non-thermal pressure support in cluster outskirts; iii) study the occurrence and mass distribution of infalling gas clumps. We illustrate the capabilities of the program with a pilot study on the cluster Abell 2142.

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Section: Joint X-ray/sz Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…The black line shows the expectation from purely gravitational collapse (Eq. (5), Voit et al 2005). The dashed and dashed-dotted vertical lines represent R 500 and R 200 , respectively.…”

Section: Joint X-ray/sz Analysismentioning

confidence: 99%

“…The red points show the spectroscopic X-ray measurements. The black curve represents the expectation of pure gravitational collapse (Voit et al 2005). …”

Section: Hydrostatic Massmentioning

confidence: 99%

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The XMM cluster outskirts project (X‐COP)

et al. 2017

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“…Analytical models and hydrodynamic simulations of halo formation neglecting radiative cooling have shown that the radial profile of the specific entropy of the hot gas generated by accretion shocks roughly follows a powerlaw function of radius with a power index β ∼ 1.1 (e.g. Tozzi & Norman 2001;Voit, Kay & Bryan 2005;Lu & Mo 2007). When radiative cooling is included, the entropy profile can be modified.…”

Section: Configuration Of the Hot Halo Gasmentioning

confidence: 99%

Formation of disc galaxies in preheated media: a preventative feedback model

Lu¹,

Mo²

2014

Monthly Notices of the Royal Astronomical Society

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We introduce a semi-analytic galaxy formation model implementing a self-consistent treatment for the hot halo gas configuration and the assembly of central disks. Using the model, we explore a preventative feedback model, in which the circum-halo medium is assumed to be preheated up to a certain entropy level by early starbursts or other processes, and compare it with an ejective feedback model, in which baryons are first accreted into dark matter halos and subsequently ejected out by feedback. The model demonstrates that when the medium is preheated to an entropy comparable to the halo virial entropy the baryon accretion can be largely reduced and delayed. In addition, the preheated medium can establish an extended low density gaseous halo when it accretes into the dark matter halos, and result in a specific angular momentum of the cooling gas large enough to form central disks as extended as those observed. Combined with simulated halo assembly histories, the preventative feedback model can reproduce remarkably well a number of observational scaling relations. These include the cold baryon (stellar plus cold gas) mass fraction-halo mass relations, star formation histories, disk size-stellar mass relation and its evolution, and the number density of low-mass galaxies as a function of redshift. In contrast, the conventional ejective feedback model fails to reproduce these observational trends. Using the model, we demonstrate that the properties of disk galaxies are closely tied to the thermal state of hot halo gas and even possibly the circum-halo medium, which suggests that observational data for the disk properties and circum-galactic hot/warm medium may jointly provide interesting constraints for galaxy formation models.

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Thermodynamical Properties of the ICM from Hydrodynamical Simulations

Borgani¹,

Diaferio²,

Dolag³

et al.

Clusters of Galaxies

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Modern hydrodynamical simulations offer nowadays a powerful means to trace the evolution of the X-ray properties of the intra-cluster medium (ICM) during the cosmological history of the hierarchical build up of galaxy clusters. In this paper we review the current status of these simulations and how their predictions fare in reproducing the most recent X-ray observations of clusters. After briefly discussing the shortcomings of the self-similar model, based on assuming that gravity only drives the evolution of the ICM, we discuss how the processes of gas cooling and non-gravitational heating are expected to bring model predictions into better agreement with observational data. We then present results from the hydrodynamical simulations, performed by different groups, and how they compare with observational data. As terms of comparison, we use X-ray scaling relations between mass, luminosity, temperature and pressure, as well as the profiles of temperature and entropy. The results of this comparison can be summarised as follows: (a) simulations, which include gas cooling, star formation and supernova feedback, are generally successful in reproducing the X-ray properties of the ICM outside the core regions; (b) simulations generally fail in reproducing the observed "cool core" structure, in that they have serious difficulties in regulating overcooling, thereby producing steep negative central temperature profiles. This discrepancy calls for the need of introducing other physical processes, such as energy feedback from active galactic nuclei, which should compensate the radiative losses of the gas with high density, low entropy and short cooling time, which is observed to reside in the innermost regions of galaxy clusters.

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The baseline intracluster entropy profile from gravitational structure formation

Cited by 309 publications

References 42 publications

The XMM cluster outskirts project (X‐COP)

The XMM cluster outskirts project (X‐COP)

Formation of disc galaxies in preheated media: a preventative feedback model

Thermodynamical Properties of the ICM from Hydrodynamical Simulations

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